The U.S. Women's Soccer team kicks off its first round of Olympics play on Wednesday.
The team has won gold in four of the last five Olympics. As they fight for a fifth gold medal, the women are also waging a battle over equal pay.
Five women's players -- Hope Solo, Alex Morgan, Megan Rapinoe, Carli Lloyd and Becky Sauerbrunn -- allege that they face discrimination because they're paid less than the players on the men's national team.
They claim they're paid less per game and receive less money for daily expenses while traveling, despite the fact that they play more games than the men's team and have a better winning record.
The USSF responded to the women's EEOC complaint in May and disputed their claims. It also said it paid the five players who brought the complaint over $3 million from 2012 to 2015 -- more than the top five men.
According to the USSF, male players make more on average because their games bring in more money, they have higher attendance levels and more valuable TV rights.
Men's games brought in about $144 million between 2008 and 2015. During that period, women's games generated $53 million in revenue.
But in 2015, the women's team brought in more money. That was the year the team won the World Cup and went on a victory tour across the U.S. The team made over $23 million in revenue while the men's team made over $21 million.
According to the USSF, one reason for the pay differential is that the women have opted for a different type of contract.
The women chose an option with more financial security because, unlike the men, most female players don't have lucrative contracts with soccer clubs in other countries.
Male players are paid on a per-game basis and get bonuses from the USSF of $5,000 or more. Top female players are guaranteed a salary of $72,000, but they make less per game and receive lower bonuses. But they do get medical insurance and severance pay.
The women maintain that while they get a salary, they play -- and win -- more games. They've won four gold medals at the Olympics since women's soccer was added in 1996 and won the 2014 CONCACAF international tournament and the World Cup in 2015.
The women also complain that they get a lower per diem -- daily money for expenses like food.
The USSF attributed this inequality to the fact that the teams' collective bargaining agreements lapsed and were renegotiated in different years.
In 2015, the men renegotiated the terms of their contract, which included higher per diems.
The federation said the per diems used to be equal and "likely will be made equivalent" when the women have a new contract.
Right now the women's team is bound by its 2012 contract, which was extended until Dec. 31, 2016.